Electrolytic cell.



H. S. HATFIELD. ELECTROLYTIC CELL.

I APPLICATION FILED 0OT.12, 1907. 1,()Q1,589 Patented Aug. 22, 1911.

2 SHEETSSHBET 2.

1 II I SEEN-JUAN is to transfer the insulating substance from I betransferred.

HENRY STAFFORD HATFIELD, 0F HOVE, ENGLAND.

- ELECTROLYTIC CELL.

Specification of Letters Patent. Patented Aug. 22, 1911.

Application filed October 12, 1907. Serial No. 397,060.

To all whom 'it may concern:

Be it known that I, HENRY Srarronn HAT- FIELD, a subject of the King ofGreat Britain and Ireland, residing at 18 Palmeira Square, Hove, in thecounty of Sussex, England, have invented certain new and useful Impronents' in Electrolytic Cells, of which the following is a specification.

The invention re ates, notto electrolytic cells in general, but to cellsin which the sole result of the passage of a current is, that somesubstance is transferred from one part of the cell to another. Suchcells I call elec-. trolytic transference cells. They are thusdistinguished from other cells in'which the result of the passage of acurrent is to produce permanent changes in the strength or chemicalnature of the electrolyte, or to liberate substances from chemicalcombination or both.-

Electrolytic transference cells need to be distinguished by a name fromothers, be cause they have quite special applications andadvantages forthese applications. The

substance transferred from one part of the cell to another may bethereby rendered morepure, as in the case of the copper rcfining cell.Im ure copper serves as anode;

only copper, an not impurities, is transferred to the cathode bytheaction of the current. Again, they are used for'mcasuring pur; poses,as in the W'right mercury meter. The substance after transference alwaysappears on one-electrode; and before my invention,

the mass of substance to be transferred formed the other electrode, or apart of it. No other way of feeding the substance into the electrolytecontinuously as the deposition took place at the other electrode wasknown, and hence a number of substances, such as bromin, which areinsulators and cannot therefore be used as electrodes, could not by anyknown means be electrolytically transferred.

My invention consists'chiefiy in the use of arr-electrolyte, which candissolve, and is saturated with, an insulating substance to Suchelectrolytes can be formed to suit many substances never hithertotransferred electrolytically. Further in common with all electrolytictransference cells my electrolyte is not permanently altered incomposition bythe passage of the current; the net and sole result of thelatter one part of the cell to another by rendering I it-temporarilyunsaturated with respectto the insulating substance at one electrode.

As hereinbefore indicated, my invention relates to electrolytic cells ofthat type in which insulating substances are deposited. Previously to'my invention only one instance of this type was known and it differswidely from the cells of my invention. For con-. venience I group allcells underthetype above mentioned into two classes, one of;

which constitutes my present invention and the other of which embracesthe cell previ-' ously known. In both classes a compound of. the body tobe deposited forms a constituent of the electrolyte. This compoundls-decomposed by the electric current. At

one-electrode (hereinafter called the first electrode) the body isdeposited; at the other electrode (hereinafter called the second.elclctrode) a compound of the body to be deposited is reformed.

In the already known class the second electrode is formed ofaconducting' body capable of dissolving the body to be deposited oruniting with it, and this electrode is placed in contact with a reservesupply of the body to be deposited, so that it may always be saturatedtherewith. At this electrode, the compound decomposed is reformed, asupply of the body to be deposited being .derivcd from the electrode,and, through the latter, from the reserve supply. It may be said of thisknown class, that the second electrodeis depolarized by the body to bedeposited which is contained in it.

In the class which constitutes my present invention, (hereinafter termedthe depolarizing electrolyte class) it is not necessary for the workingof the cell that the second electrode should have the power ofdissolving the body to be deposited or of uniting withit, and the saidelectrode need not be in contact with the reserve supply of the body tobe deposited. By my invention, the electrolyte is capable of dissolvingthe body to be deposited and is saturated therewith through being incontar" with a reserve supply of the said body. At the second electrodethecompound decomposed or one similar to it but containing less of thebody to be deposited is reformed. the supply of the body to be depositedbringdcrin-d not from the second electrode but directly from the I againsaturate it.

' I may arrange to hermetically seal the and further, that when theelectrolyte has been unsaturated by abstraction of the deposited body,contact with the latter will cell, and pivot it so that by turning itthe depositedbody may be returned to the reservoir from whichthe'solution at the sec: ond electrode is regenerated; If the body to bedepositedbe aliquid I may usea self-' emptying siphon to measure it andgive a multiple dial effect, as employed in the measurementof mercury byWright, Patent No. 702,844, dated 17th June, 1902. Or .I

may: cause the liquid or gas deposited to flow into a. number oftubes-so, arranged that when'one isfull the next thereto will receivethe liquid or-gas. V

In order that'lny invention may be more readily understood,. Ishallfnow" roceed to describe it withreference to tie accompanyingsheet-of drawings in which,

Figiire 1 is an end elevation of the cell constituting a meter asaforesaid; Fig. 2 is a side elevation'thereof; and Fig. 3 a sectionon'the line a,-b of Fig. 1'; Fig. 4 shows another "house service meterwhich diifers from that shown in Figs; -1, 2 and. 3 in that instead of aliquid being deposited at gas is deposited; Fig. 5 shows an electrolyticcell in which the body to be deposited is a solid Fig. 6 illustrates acase in which a liquid or solid is deposited but in which the electricalresistance of the cell is arranged to he as low as possible; 7illustrates a cell designed for the purification of a gas byelcetro-deposition; and Fig. 8 illustrates a modifiediorm of cell forpurifying gas by electro-deposition.

Referring now to I igs. 1,2 and 3, the cell S is of glass divided by thepartition H into two parts. -The electrolyte is a dilute solution ofhydro-bromic acid saturated with bromin. A pool of bromin 0 lies on thebottom of the cell; in the right-hand compart-merit E itis at a higherlevel and passes into the left hand compartment and keeps the level ofthe pool there constant through a hole at F. The cathode B consists ofan iridium plate close above the surface of the bromin. The anode A isof platinum and is placed in a'funnel ending in a reading tube 1) (Figs.1 and 3) which is formed as a self-emptying siphon. IVhen current ispassed between the electrodes A (in this case the positive electrode)and I5 bromin is deposited on A. and slnce the solution is alreadysaturatedwith 'bromin the latter drops -froin. the electrode A into thencas uring tube D. At the electrode B hydrobromic acid is formed by thecombination ofthe hydrogen (there released) with the greater part of thecurrent passingthrough low resistance Gris placed in parallel thethislow resistance. "The cell is pivoted S0 that it can be inverted toreturn the bromin' to the reservoir after-a manner well known, inconnection with'mercury electrolytic 1neters. The high resistance isconstructed partially of a pure metal such as;1roi'1hav' mg a largepositive temperature co efiicie'nt' and partially of a suitableresistance? alloy such as-manganin. The ro ortionof the two metals issuch that the whole circuit shall have an approximately constantresistance with change of temperature.

In Fig. at, I illustrate a meter which differs from that previouslydescribed in that it is adapted for the measurement of a gas"measurement of a liquid so liberated. The gas designed to be liberatedinthe specific liberated by the current instead of the f case now underdescription is chlorin so that this gaswill be deposited as" inthe'former case at the anode, A. The electrolyte employed is a solutionof ferric chldrid saturatcd 'with chlorin of which there is a' re-'serve supply in the space C. The chlorin liberated at the anode A iscollected at the upper part of the depositing tube D which soconstructed as to return upon itself for pur mses of easy resetting. Theequivalent of the liquid displaced in the depositing tube overflows intothe tube E The elec trolyte which is converted from ferric to ferrouschlorid at the. electrode 13 by the action. of the current isreconverted by contact with the chlorin in the space C, that is to sayby purely chemical action, into fcr-' ric chlorid. Measurement may bemade of the amount of gas collected in the tube D and orhy measurementof the liquid displaced into the tube E. A scale such for 1 example asis shown in this figure as well as in Fig. I may be employed f r themeasurement of the deposited body. I. have spoken of the gas beingliberated in this case attlieanode. I do'not imply that in other casesthe body to be deposited is neces: sarily liberated at the anode. Itwill be obvious that the electrode at which the may be introduced as itis dissolved away.

in thebath. The solid deposited on A may fall of itself into the tube Ebut if it does notdo so it may be periodically or continuously scrapedaway from the electrode. As an illustrative case I may mention thepurification of sulfur. 'lh'eelectrolyte employed in this case will bea" strong solution of sulfid of sodium saturated with sulfur. \Vhilethese cells exhibit the principles of my invention in its simplest formthey have the drawback that the electrodes are comparatively wideapartin order that solution depleted at the second electrode shall reachthe first without, being resaturated with the substance to be deposited.In the use of such cells for the purification on a commercial scale ofsubstances this would lead to an excessive waste of electric energy inthe resistance .ofthe cell. For this purpose I prefer to place theelectrodes close together and by suitable, means cause a circulation ofthe liquid away from the first electrode over the second. Theelectrolyte after passing the second is then brought into contact wit-hsubstance and saturated, fin; lly returning to its starting position.Two such constructions are figured diagrammatically in Figs. 6 and 7. InFig. (3 which is suited particularly for purifying a liquid or a solidthe two electrodes are placed close together at A and B and acirculation is maintained by a pump D in the direction shown by theairows. In the con'ipartment C the liquid or soli(l.i-' brought intothorough contact with the substance which is to be dissolved and whichlies in a pool or mass at the bottom of the said compartment. Theelectrodes are pierced with holes to allow of tree circulation of liquidthrouglrthem.

Fig. 7 illustrates a cell which is adapted f relect-ro-dtposition or gasby deriving it from a mixture with other gases. The electrolytc iscontained in the cell A. it. ll, F, the first electrode. on which gas isdeposited. being the electrode A. and the second electrode 15. The firstel ctrode A. is formed in parallel bars on a grating so that the gaswhich is deposited at its under side can easily escape upward. Electrodel, is porous and the liquid gradually periolatcs through it falling ontrays in the absorption chamer through this absorption chamber theimpure or mixed gas from which the gas to be deposited has to beseparated, is passed. The electrolyte on reaching the bottom of thischamber is restored to the upper part of the cell by a pump at F. At theelectrode B the electrolyte becomes unsaturated with respect to the gasto'be deposited and in passing down the absorption chamber becomesresaturated therewith. This apparatus will not be eflieient as appliedto the deposition of a gas such as chlorin, the solubility of which inmost electrolytes varies considerably with the pressure. If the cell inFig.7 were used for the deposit-ion of chlorin the liquid beingsaturated with chlorin atatmospheric pressure. by contact with theelectrode A would lose a certain amount of free chlorin by the action ofthe electrode B and in passing through the absorption chamber CT inwhich the gas con-' tains chlorin at a lower partial pressure than theatmospheric would not be resaturated here to the strength correspondinto atmospheric pressure. In Fig. 8 this di ficulty is avoided becausethe gas-absorption chamber D is connected with the cellby a long pipe F,the other details being similar to Fig. 7. It is then possible to eitherincrease the pressure in D above the atmospheric by the amountcorresponding to the head of liquid in the pipe 1*,or to decrease thepressure above the cell at the top of F 8 by a corresponding amount. Thecondition to be fulfilled is that the pressure of the pure gas on theliquid near the-electrode at which it is given off should be equal to orless than thepartial pressure of this "as in the mixed gases in D.

1. An electrolytic transference, cell consisting of an electrolyte inwhich any insu lating substance deposited b the passage of the currentthrough the cell is soluble and with which it is saturated; twoelectrodes on one of which the insulatin substance is deposited and atthe other 0 which the electrolyte becomes unsaturated with respect tothe substance deposited without perma- 1 nent alteration of theelectrolyte; and a Supply of the insulating substance deposited resaturating by contact therewith the liquid which has becomeunsaturated, the sole result being to transfer the insulating sub- 1stance from one part of the cell to another, substantially as described.

An electrolytic transference cell consisting of an electrolyte'in whichany insulating substancedeposited by the passage of the current throughthe cell is soluble and. with which it is satul'attd; twoelectrodes onone of which the insulating substance is deposited and at the other ofwhich the electrolyte becomes unsaturated with respect to the substancedeposited without per manent alteration of the electrolyte; a supply ofthe insulating substance deposited lesaturating by contact therewith theliquid whichhas become unsaturated; and a device substantially asdescribed.

for causing the circulation of the electrolyte.

with reference to the resaturating substance,

3. An electrolytic transference cellconsistingof an electrolyte in whichany substance deposited by the passage of the current through the cellis soluble;'two electrodes on oneof which the substance is de-' positedand at the other of which the,electi'olyte becomes unsaturated withrespect to' the, substance deposited; an absorption chaiuber containinga'supply of the substance deposited resaturating by contact therewiththe liquid which has become unsaturated; aud ahead of liquid bet-weenthe electrodes and. the absorption chamber; so that the pressure oil-theelectrolyte at the' electrodes may be lower than that in the abSOrptiO'nchamber, substantially as de- ;20"scribed." v

4.'An electrolytic transference cell con sisting of an electrolyte inwhich any substance deposited by the passageof the currentth'roughthecell is soluble; two electrodes, one of-them being porous and on oneof which the substance 1s deposited and at the other of which theelectrolyte-rhizomes unsaturated, with respect to the substancedeposited; and a supply of the substancedeposited resaturating bycontact therewith the liquid which has become unsaturated, substantiallyas described.

In "Witness whereof I have signed my name to this specification in thepresence of. two subscribing witnesses. v

I STAFFORD HAHF IELD. Witnesses! 1 H. D. JA EsoN,

F. RAND.

